This invention concerns a helical zone refining process employing a common solvent for the material to be purified and the impurity.
Zone melting of impure materials in helical zone refiners is known. See, for example, Pfann, Zone Melting, Second Edition, John Wiley and Sons, New York, 1966, pages 76 and 77. Use of a solvent in zone refining is known; see, for example, Pfann, ibid, at pages 56 to 58. See also, Nicolau, J. Mater. Sci. 5, 623 to 639 and J. Mater. Sci. 6, 1049 to 1060; and U.S. Pat. No. 3,449,087 (Saylor). However, no disclosure has been found concerning zone refining with a helical solution zone.